Cutter for biopsy device

ABSTRACT

A biopsy device and method are provided for obtaining tissue samples. The biopsy device can include a probe assembly having a cannula and a cutter assembly. The cutter assembly includes a hollow cutter, and the hollow cutter can be removed from the probe assembly without disassembling the probe assembly. The method can include the steps of positioning the tissue receiving port in the tissue to be sampled; removing the cutter from the biopsy device; imaging the biopsy site associated with the tissue receiving port of the biopsy device after removing the cutter from the biopsy device; inserting the cutter into the biopsy device; and severing tissue received in the tissue receiving port with the cutter.

CROSS REFERENCE TO RELATED APPLICATIONS

This applications cross references and incorporates by reference thefollowing commonly assigned patent applications: U.S. application Ser.No. 10/785,755 “Biopsy Device with Variable Speed Cutter Advance” filedFeb. 24, 2004 in the name of Thompson et al.; U.S. patent applicationSer. No. 10/676,944 “Biopsy Instrument with Internal Specimen CollectionMechanism” filed Sep. 30, 2003 in the name of Hibner et al.; and U.S.patent application Ser. No. 10/732,843 “Biopsy Device with Sample Tube”filed Dec. 10, 2003 in the name of Cicenas et al.

FIELD OF THE INVENTION

The present invention relates in general to biopsy devices, and moreparticularly to biopsy devices having a cutter for severing tissue.

BACKGROUND OF THE INVENTION

The diagnosis and treatment of tissue is an ongoing area ofinvestigation. Medical devices for obtaining tissue samples forsubsequent sampling and/or testing are know in the art. For instance, abiopsy instrument now marketed under the tradename MAMMOTOME iscommercially available from Ethicon Endo-Surgery, Inc. for use inobtaining breast biopsy samples.

The following patent documents disclose various biopsy devices and areincorporated herein by reference in their entirety: U.S. Pat. No.6,273,862 issued Aug. 14, 2001; U.S. Pat. No. 6,231,522 issued May 15,2001; U.S. Pat. No. 6,228,055 issued May 8, 2001; U.S. Pat. No.6,120,462 issued Sep. 19, 2000; U.S. Pat. No. 6,086,544 issued Jul. 11,2000; U.S. Pat. No. 6,077,230 issued Jun. 20, 2000; U.S. Pat. No.6,017,316 issued Jan. 25, 2000; U.S. Pat. No. 6,007,497 issued Dec. 28,1999; U.S. Pat. No. 5,980,469 issued Nov. 9, 1999; U.S. Pat. No.5,964,716 issued Oct. 12, 1999; U.S. Pat. No. 5,928,164 issued Jul. 27,1999; U.S. Pat. No. 5,775,333 issued Jul. 7, 1998; U.S. Pat. No.5,769,086 issued Jun. 23, 1998; U.S. Pat. No. 5,649,547 issued Jul. 22,1997; U.S. Pat. No. 5,526,822 issued Jun. 18, 1996, and U.S. PatentApplication 2003/0199753 published Oct. 23, 2003 to Hibner et al.

Researchers in the medical device area continue to seek new and improvedmethods and devices for cutting, handling, and storing tissue samples.

SUMMARY OF THE INVENTION

In one embodiment, the present invention provides a method of performinga biopsy. The method can include the steps of providing a biopsy devicecomprising a cannula having a tissue receiving port and a cutterassembly comprising a hollow cutter disposed at least partially withinthe cannula for translation with respect to the cannula, the cutter forsevering tissue drawn into the tissue receiving port; positioning thetissue receiving port in the tissue to be sampled; removing the cutterfrom the biopsy device; imaging the biopsy site associated with thetissue receiving port of the biopsy device after removing the cutterfrom the biopsy device; inserting the cutter into the biopsy device; andsevering tissue received in the tissue receiving port with the cutter.

In another embodiment, the present invention provides a biopsy devicewhich includes a probe assembly. The probe assembly includes a cannulaand a cutter assembly. The cutter assembly includes a hollow cutterdisposed for translation with respect to the cannula. The hollow cutteris removable from the probe assembly without disassembling the probeassembly and without removing the cannula from the probe assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

While the specification concludes with claims particularly pointing outand distinctly claiming the present invention, it is believed the samewill be better understood by reference to the following description,taken in conjunction with the accompanying drawings in which:

FIG. 1 is a partial isometric and partial schematic view of a biopsyinstrument according to one embodiment of the present invention, whichincludes a handpiece for the collection of soft tissue;

FIG. 2 is an isometric view of the probe assembly separated from theholster;

FIG. 3 a is cross-sectional isometric view of the probe assembly takenalong line 3-3 in FIG. 2 with the cutter & carriage assembly positionedat the proximal end position;

FIG. 3 b is cross-sectional isometric view of the probe assembly takenalong line 3-3 in FIG. 2 with the cutter & carriage assembly positionedbetween the proximal and distal end positions;

FIG. 3 c is cross-sectional isometric view of the probe assembly takenalong line 3-3 in FIG. 2 with the cutter & carriage assembly positionedat the distal end position;

FIG. 4 is an exploded isometric view of the probe assembly of FIG. 2;

FIG. 5 a is a schematic diagram of the biopsy needle illustrating thefluid forces and cutter when the cutter is in a proximal end position atthe initiation of a cutting cycle;

FIG. 5 b is a schematic diagram similar to FIG. 5 a, illustrating thecutter and fluid forces as the cutter translates distally to sever atissue sample;

FIG. 5 c is a schematic diagram similar to FIG. 5 a, illustrating thefluid forces and cutter when the cutter has closed the aperture andsevered the tissue sample;

FIG. 5 d is a schematic diagram similar to FIG. 5 a, illustrating thefluid forces and cutter as the cutter has reached the distal endposition and a tissue sample is aspirated to the tissue storing assemblyat the conclusion of a cutting cycle;

FIG. 6 is an isometric view of the rotary drive shaft illustrating adrive coupling configuration;

FIG. 7 is an isometric view of an alternative embodiment for the cutterand drive carriage in which the cutter is removable from the probeassembly;

FIG. 8 is an isometric view similar to FIG. 7, illustrating the cutterand rear tube disengaged from the carriage and rotary drive gear forremoval from the probe assembly;

FIG. 9 a is an isometric view of the distal end of the biopsy needleillustrating the needle lumen and divider in greater detail;

FIG. 9 b is a top isometric view of the distal portion of the biopsyneedle illustrating the side tissue receiving port in greater detail;

FIG. 10 is an isometric view of an alternative embodiment for the biopsyneedle;

FIG. 11 is an exploded isometric view of the biopsy needle shown in FIG.10;

FIG. 12 is a more detailed top isometric view of the aperture componentshown in FIG. 11;

FIG. 13 is a more detailed bottom isometric view of the aperturecomponent shown in FIG. 11;

FIG. 14 is an isometric view of a serial tissue stacking assembly;

FIG. 15 a is an isometric view of the probe assembly of FIG. 2 and thedistal end of the serial tissue stacking assembly of FIG. 14, showingconnectors for attaching the serial tissue storing assembly to the probeassembly;

FIG. 15 b is an isometric view similar to FIG. 15 a, illustrating theprobe assembly attached to the serial tissue storing assembly;

FIG. 16 is a side cross-sectional view taken along line 16-16 of theserial tissue stacking assembly of FIG. 14;

FIG. 17 is a side cross-sectional view taken along line 17-17 of FIG.16, illustrating the vacuum communication holes of the serial tissuestacking tube in greater detail;

FIG. 18 is an isometric view of the translating flexible rod;

FIG. 19 is an isometric view showing the reciprocating member and lowerconnector in greater detail;

FIG. 20 is an isometric view showing the probe connectors and distal endof the tissue sample storage tube in greater detail;

FIG. 21 is a detailed isometric view of the tissue retrieval mechanismshown in FIG. 14, with the outer sleeve of the mechanism in a closedposition;

FIG. 22 is a detailed isometric view of the tissue retrieval mechanismof FIG. 21, showing the outer sleeve of the mechanism in an openposition;

FIG. 23 is an exploded isometric view of the mechanism of FIG. 21;

FIG. 24 shows a flexible push rod in the form of a plunger for use inremoving samples;

FIG. 25 is an isometric view showing removal of samples;

FIG. 26 a is a schematic illustration of an embodiment of a separabletissue storage tube;

FIG. 26 b is an isometric sectional view similar to FIG. 26 a,illustrating the vacuum lumen being peeled away from the tissue lumen;

FIG. 26 c is an isometric view similar to FIG. 26 a, illustrating thetissue lumen removed from the vacuum lumen;

FIG. 27 a is an isometric sectional view of an alternative embodimentfor a separable tissue sample storage tube;

FIG. 27 b is an isometric sectional view similar to FIG. 27 a,illustrating the vacuum lumen being peeled away from the tissue lumen;

FIG. 28 is an isometric sectional view of a third embodiment for aseparable tissue storage tube in which the tissue and vacuum lumens areseparately extruded and attached together by a mechanical latch;

FIG. 29 is an isometric view of an alternative embodiment for the serialtissue stacking assembly of FIG. 14, in which the proximal end of thetissue lumen is attached to a tissue stop rather than the tissueretrieval mechanism;

FIG. 30 is an exploded isometric view of the alternative serial tissuestacking assembly embodiment shown in FIG. 29;

FIG. 31 a is an isometric sectional view of the alternative serialtissue stacking assembly embodiment shown in FIG. 29 showing thepositions of the connectors, sample tube and translating rod of theserial tissue storing assembly when the cutter and drive carriage areadvanced distally in an initial cutting cycle;

FIG. 31 b is an isometric sectional view similar to FIG. 31 a, showingthe positions of the connectors, sample tube and translating rod whenthe cutter and drive carriage are retracted following the initialcutting cycle;

FIG. 31 c is an isometric sectional view similar to FIG. 31 a, showingthe positions of the connectors, sample tube and translating rod of theserial tissue storing assembly when the cutter and drive carriage areadvanced distally during a second cutting cycle;

FIG. 31 d is an isometric sectional view similar to FIG. 31 a, showingthe positions of the connectors, sample tube and translating rod of theserial tissue storing assembly when the cutter and drive carriage areretracted following the second cutting cycle;

FIG. 32 is an isometric view of a parallel tissue stacking assembly forthe present invention;

FIG. 33 is an exploded isometric view of the parallel tissue stackingassembly of FIG. 32;

FIG. 34 is a bottom isometric view of the tissue storage component shownin FIGS. 32 and 33;

FIG. 35 is an isometric view of the distal end of the parallel tissuestacking assembly of FIG. 32, with the tissue storage component removed;

FIG. 36 a is a more detailed isometric view of the cam member of FIG.33, showing the cam member in a retracted position at the beginning of acutting cycle, with the position of a pair of bosses shown in phantom;

FIG. 36 b is a more detailed isometric view similar to FIG. 36 a,showing the cam member in an advanced position during the cutting cycle,and a pair of bosses in phantom, with one of the bosses deflecting thecamming surface;

FIG. 36 c is a more detailed isometric view similar to FIG. 36 a,showing the cam member in a retracted position at the conclusion of acutting cycle, with the position of a boss at the conclusion of thecutting cycle shown in phantom;

FIG. 37 is an exploded isometric view of a cable driven drive assemblyfor the holster viewed in the proximal direction;

FIG. 38 a is an isometric view of a probe assembly base unit for use ina mammography guided biopsy procedure;

FIG. 38 b is an isometric view of a probe and probe assembly base unitfor use in a mammography guided biopsy procedure;

FIG. 39 is an isometric view of a second embodiment of a probe assemblybase unit for use in an ultrasound guided biopsy procedure;

FIG. 40 is an isometric view of a third embodiment of a probe assemblybase unit for use in an MRI guided biopsy procedure; and

FIG. 41 is an isometric view of an MRI localization depth gage forinterfacing the probe assembly with an MRI unit.

DETAILED DESCRIPTION OF THE INVENTION

The present invention pertains to a biopsy device for obtaining a tissuesample from within a body. The biopsy device can have a reduced cuttingstroke length as compared to device such as commercially availableMammotome brand biopsy devices. Reducing the cutting stroke lengthdecreases the time to acquire each sample, and also the overall size ofthe biopsy device, thereby enhancing the versatility and ergonomics ofthe device. The reduced stroke length of the cutter enables many of thesame probe components to be used in all three primary imagingenvironments: mammography, ultrasound and MRI. In addition, the presentinvention enables the sequential collection and storage of tissuesamples. Tissue samples may be removed from the biopsy device andexamined in real-time, as well as sequentially stored for subsequentretrieval at the conclusion of the biopsy procedure. Sequentiallystoring tissue samples eliminates the need to immediately remove eachsample from the device following sampling, thereby further reducing thesample acquisition time.

FIG. 1 shows a core sampling biopsy instrument according to the presentinvention comprising a handpiece identified generally as numeral 30.Handpiece 30 can be held comfortably in a single hand, and can bemanipulated with a single hand. Handpiece 30 can include a probeassembly 32 and a detachably connected holster 34. Probe assembly 32 canbe operatively connected to a vacuum source 36, such as by a first,lateral tube 40 and a second, axial tube 42. First and second tubes 40,42 can be made from a flexible, transparent or translucent material,such as silicon tubing, PVC tubing or polyethylene tubing. Using atransparent material enables visualization of the matter flowing throughtubes 40, 42.

First tube 40 can includee a Y connector 44 for connecting to multiplefluid sources. A first proximal end of Y connector 44 can extend to afirst solenoid controlled rotary valve 48 in a control module 46, whilethe second proximal end of the Y connector can extend to a secondsolenoid controlled rotary valve 51 in control module 46. The firstsolenoid controlled rotary valve 48 in control module 46 can be operableto connect either the vacuum source 36 or the compressed air source 38to lateral tube 40. It is understood within this specification thatcompressed air means air pressure at or above atmospheric pressure. Inone configuration, when valve 48 is activated, vacuum is supplied totube 40 from vacuum source 36, and when valve 48 is not activated,pressurized air from compressed air source 38 is supplied through tube40. The solenoid associated with valve 48 can be controlled by amicroprocessor 49 in control module 46, as indicated by dashed line 47.Microprocessor 49 can be employed to adjust the position of valve 48automatically based upon the position of a cutter movably supportedwithin probe assembly 32. The second solenoid controlled rotary valve 51in control module 46 can be employed to either connect a saline supply50 (such as a saline supply bag, or alternatively, a pressurizedreservoir of saline) to a tube 188 or to seal off the proximal end oftube 188. For instance, rotary valve 51 can be activated bymicroprocessor 49 to supply saline when a switch on handpiece 30 isactuated. When rotary valve 51 is activated, first rotary valve 48 canbe automatically deactivated (such as by microprocessor 49) to preventthe interaction of vacuum and saline within lateral tube 40. A stopcock58 may be included in lateral vacuum tube 40 to allow for a syringeinjection of saline directly into the tube 40, if desired. For instance,a syringe injection can be employed to increase the saline pressure inthe tube to dislodge any clogs that may occur, such as tissue cloggingfluid passageways.

In one embodiment, axial vacuum tube 42 can be employed to communicatevacuum from source 36 to probe assembly 32 through a tissue storageassembly 52. Axial tube 42 can provide vacuum through the cutter withinprobe assembly 32 to assist in prolapsing tissue into a side tissueaperture aperture prior to cutting. After cutting occurs, the vacuum inaxial line 42 can be employed to help draw a severed tissue sample fromprobe assembly 32 and into tissue storage assembly 52, as will bedescribed in further detail below.

Holster 34 can include a control cord 54 for operationally connectinghandpiece 30 to control module 46, and a flexible rotatable shaft 55connecting the holster to a drive motor 45. A power source 56 can beemployed to provide energy to control module 46 for powering holster 34via control cord 54. Switches 60 are mounted on holster upper shell 62to enable an operator to use handpiece 30 with a single hand. One-handedoperation allows the operator's other hand to be free, for example, tohold an ultrasonic imaging device. Switches 60 can include atwo-position rocker switch 64 for manually actuating the motion of thecutter (e.g. forward movement of the rocker switch moves the cutter inthe forward (distal) direction for tissue sampling and rearward movementof the rocker switch actuates the cutter in the reverse (proximal)direction). Alternatively, the cutter could be automatically actuated bycontrol module 46. An additional switch 66 can be provided on holster 34for permitting the operator to activate saline flow on demand intolateral tube 40 (for instance, switch 66 can be configured to operatevalve 51 for providing saline flow to tube 40 when switch 66 isdepressed by the user).

FIG. 2 shows probe assembly 32 disconnected from holster 34. Probeassembly 32 includes an upper shell 70 and a lower shell 72, each ofwhich may be injection molded from a rigid, biocompatible plastic, suchas a polycarbonate. Upon final assembly of probe assembly 32, upper andlower shells 70, 72 can be joined together along a joining edge 74 byany of a number of methods well-known for joining plastic parts,including, without limitation, ultrasonic welding, snap fasteners,interference fit, and adhesive joining.

FIGS. 3 a, 3 b, 3 c, and 4 illustrate probe assembly 32 in greaterdetail. FIG. 3 a depicts the cutter assembly and carriage retractedproximally. FIG. 3 b depicts the cutter assembly and carriage partiallyadvanced. FIG. 3 c depicts the cutter assembly and carriage advanceddistally. As shown in FIGS. 3 a-c, the probe assembly can include abiopsy needle 80 located at a distal end of probe assembly 32 forinsertion into a patient's skin to obtain a tissue sample. Needle 80comprises an elongated, metallic cannula 82, which can include an upperlumen, such as an upper cutter lumen 83 for receiving a cutter 100 (asshown in FIG. 5 a), and a lower lumen, such as a lower lumen 84 forproviding a fluid passageway. Cutter 100 can be disposed within cannula82, and can be coaxially disposed within lumen 83.

Cannula 82 can have any suitable cross-sectional shape, including acircular or oval shaped cross-section. Adjacent and proximal of thedistal end of cannula 82 is a side (lateral) tissue receiving port 86for receiving the tissue to be severed from the patient. A sharpened tipof needle 80 can be formed by a separate endpiece 90 attached to thedistal end of cannula 82. The sharpened tip of endpiece 90 can be usedto pierce the patients skin so that the side tissue receiving port canbe positioned in the tissue mass to be sampled. Endpiece 90 can have atwo-sided, flat-shaped point as shown, or any number of other shapessuitable for penetrating the soft tissue of the patient.

The proximal end of needle 80 can be attached to a union sleeve 92having a longitudinal bore 94 therethrough, and a transverse opening 96into a widened center portion of the bore. The distal end of lateraltube 40 can be inserted to fit tightly into transverse opening 96 ofunion sleeve 92. This attachment allows the communication of fluids (gasor liquid) between the lower lumen and the lateral tube 40.

The cutter 100, which can be an elongated, tubular cutter, can bedisposed at least partially within upper lumen 83, and can be supportedfor translation and rotation within lumen 83. Cutter 100 can besupported within needle lumen 84 so as to be translatable in both thedistal and proximal directions. Cutter 100 can have a sharpened distalend 106 for cutting tissue received in upper lumen 83 through sidetissue receiving port 86. The cutter 100 may be formed of any suitablematerial, including without limitation a metal, a polymer, a ceramic, ora combination of materials. Cutter 100 can be translated within lumen 83by a suitable drive assembly such that distal end 106 travels from aposition proximal of the side tissue port 86 (illustrated in FIG. 3 a)to a position distal of side tissue port 86 (illustrated in FIG. 3 c),in order to cut tissue received in lumen 83 through the side tissue port86. In an alternative embodiment, an exterior cutter can be employed,with the exterior cutter sliding coaxially with an inner cannularneedle, and the inner needle can include a side tissue receiving port.

Union sleeve 92 is supported between probe upper and lower shells 70, 72to ensure proper alignment between cutter 100 and the union sleeve. Thecutter 100 can be a hollow tube, with a lumen 104 extending axiallythrough the length of cutter 100. As shown in FIG. 4, the proximal endof cutter 100 can extend through an axial bore of a cutter gear 110.Cutter gear 110 may be metallic or polymeric, and includes a pluralityof cutter gear teeth 112. Cutter gear 110 can be driven by a rotarydrive shaft 114 having a plurality of drive gear teeth 116 designed tomesh with cutter gear teeth 112. Drive gear teeth 116 can extend alongthe length of drive shaft 114 so as to engage cutter gear teeth 112 asthe cutter 100 translates from a proximal most position to a distal mostposition, as illustrated in FIGS. 5 a-5 c. Drive gear teeth 116 can bein continual engagement with cutter gear teeth 112 to rotate cutter 100whenever drive shaft 114 is rotatably driven. Drive shaft 114 rotatescutter 100 as the cutter advances distally through tissue receiving port86 for the cutting of tissue. Drive shaft 114 may be injection moldedfrom a rigid engineered plastic such as liquid crystal polymer materialor, alternatively, could be manufactured from a metallic or non-metallicmaterial. Drive shaft 114 includes a first axial end 120 extendingdistally from the shaft. Axial end 120 is supported for rotation withinprobe lower shell 72, such as by a bearing surface feature 122 molded onthe inside of the probe shell. Similarly, a second axial end 124 extendsproximally from rotary drive shaft 114 and is supported in a secondbearing surface feature 126 which can also be molded on the inside ofprobe lower shell 72. An O-ring and bushing (not shown) may be providedon each axial end 120, 124 to provide rotational support and audiblenoise dampening of the shaft 114 when rotary drive shaft 114 is mountedin probe shell 72.

As shown in FIGS. 3 a, 3 b, 3 c, and 4, a drive carriage 134 is providedin probe assembly 32 to hold cutter gear 110, and carry the cutter gearand attached cutter 100 during translation in both the distal andproximal directions. Drive carriage 134 is preferably molded from arigid polymer and has a cylindrically-shaped bore 136 extending axiallytherethrough. A pair of J-shaped hook extensions 140 extend from oneside of drive carriage 134. Hook extensions 140 rotatably support cutter100 on either side of cutter gear 110 to provide proximal and distaltranslation of the cutter gear and cutter during proximal and distaltranslation of drive carriage 134. Hook extensions 140 align cutter 100and cutter gear 110 in the proper orientation for cutter gear teeth 112to mesh with drive gear teeth 116.

Drive carriage 134 is supported on a translation shaft 142. Shaft 142 issupported generally parallel to cutter 100 and rotary drive shaft 114.Rotation of the translation shaft 142 provides translation of thecarriage 134 (and so also cutter gear 110 and cutter 100) by employing alead screw type drive. Shaft 142 includes an external lead screw threadfeature, such as lead screw thread 144, on its outer surface. The screwthread 144 extends into a bore 136 in carriage 134. The screw thread 144engages an internal helical threaded surface feature provided on theinner surface of bore 136. Accordingly, as shaft 142 is rotated, thecarriage 134 translates along the threaded feature 144 of the shaft 142.The cutter gear 110 and the cutter 100 translate with the carriage 134.Reversing the direction of rotation of shaft 142 reverses the directionof translation of the carriage 134 and the cutter 100. Translation shaft142 may be injection molded from a rigid engineered plastic such asliquid crystal polymer material or, alternatively, could be manufacturedfrom a metallic or non-metallic material. Translation shaft 142 withlead screw thread feature 144 can be molded, machined, or otherwiseformed. Likewise, carriage 134 can be molded or machined to include aninternal helical thread in bore 136. Rotation of shaft 142 drives thecarriage and cutter gear 110 and cutter 100 in the distal and proximaldirections, depending upon the direction of rotation of shaft 142, sothat cutter 100 translates within probe assembly 32. Cutter gear 110 isrigidly attached to cutter 100 so that the cutter translates in the samedirection and at the same speed as drive carriage 134.

In one embodiment, at the distal and proximal ends of lead screw thread144, the helical thread is cut short so that the effective pitch widthof the thread is zero. At these distal most and proximal most positionsof thread 144, translation of drive carriage 134 is no longer positivelydriven by shaft 142 regardless of the continued rotation of shaft 142,as the carriage effectively runs off the thread 144. Biasing members,such as compression coil springs 150A and 150B (FIGS. 3 a-c), arepositioned on shaft 142 adjacent the distal and proximal ends of thescrew thread 144. Springs 150A/B bias carriage 134 back into engagementwith lead screw thread 144 when the carriage runs off the thread 144.While shaft 142 continues rotating in the same direction, the zero pitchwidth thread in combination with springs 150A/B cause carriage 134 and,therefore, cutter 100 to “freewheel” at the end of the shaft. At theproximal end of the threaded portion of shaft 142, the carriage engagesspring 150A. At the distal end of the threaded portion of shaft 142, thecarriage engages spring 150B. When the carriage runs off the screwthread 144, the spring 150A or 150B engages the carriage 134 and biasesthe carriage 134 back into engagement with the screw thread 144 of shaft142, at which point continued rotation of the shaft 142 again causes thecarriage 134 to run off the screw thread 144. Accordingly, as long asrotation of shaft 142 is maintained in the same direction, the carriage134 (and cutter 100) will continue to “freewheel”, with the distal endof the cutter 106 translating a short distance proximally and distallyas the carriage is alternately biased onto the thread 144 by spring 150Aor 150B and then run off the screw thread 144 by rotation of shaft 142.When the cutter is in the distal most position shown in FIG. 3 c, withthe distal end 106 of cutter positioned distal of side tissue port 86,spring 150B will engage carriage 134, and repeatedly urge carriage 134back into engagement with screw thread 144 when carriage 134 runs offthe screw thread 144. Accordingly, after the cutter 100 is advanced suchthat the distal end 106 of the cutter translates distally past the sidetissue port 86 to cut tissue, to the position shown in FIG. 3 c,continued rotation of the shaft 142 will result in the distal end 106oscillating back and forth, translating a short distance proximally anddistally, until the direction of rotation of shaft 142 is reversed (suchas to retract the cutter 100 distally to the position shown in FIG. 3a.) The slight movement of carriage 134 into engagement with the screwthread and out of engagement with the screw thread 144 against thebiasing force of spring 150B, causes the distal end 106 of cutter 100 torepetitively reciprocate a short distance within cannula 82, whichdistance can be about equal to the pitch of threads 144, and whichdistance is shorter than the distance the cutter travels in crossing theside tissue port 86. This reciprocal movement of the cutter can providealternate covering and uncovering of at least one fluid passagewaydisposed distally of the side tissue port, as described below.

The zero pitch width ends of lead screw thread 144 provide a definedstop for the axial translation of cutter 100, thereby eliminating theneed to slow carriage 134 (i.e. cutter 100) as it approaches the distaland proximal ends of the thread. This defined stop reduces the requiredpositioning accuracy for carriage 134 relative to shaft 142, resultingin reduced calibration time at the initialization of a procedure. Thefreewheeling of carriage 134 at the distal and proximal most positionsof translation shaft 142 eliminates the need to rotate the shaft aprecise number of turns during a procedure. Rather, translation shaft142 only needs to translate at least a minimum number of turns to insurecarriage 134 has translated the entire length of lead screw thread 144and into the zero width thread. Additionally, the freewheeling ofcarriage 134 eliminates the need to home the device, allowing probeassembly 32 to be inserted into the patient's tissue without first beingattached to holster 34. After probe assembly 32 is inserted, holster 34is attached and sampling can be commenced.

As shown in FIG. 4, a non-rotating rear tube 152 can be provided whichtube 152 can extend proximally from the proximal end of cutter 100 justproximal of cutter gear 110. Rear tube 152 can be hollow and can havesubstantially the same inner diameter as cutter 100, and may becomprised of the same material as the cutter. A seal 154 can bepositioned between cutter 100 and rear tube 152 to enable the cutter torotate relative to the tube while providing a pneumatic seal between therear tube 152 and the cutter 100. A rear lumen 156 can extend throughthe length of tube 152 and can be aligned with lumen 104 in cutter 100.Rear lumen 156 transports excised tissue samples from lumen 104 throughprobe assembly 32 to the tissue storage assembly 52. Lumen 104 and rearlumen 156 are axially aligned to provide a continuous, generallystraight line, unobstructed passageway between tissue receiving port 86and tissue storage assembly 52 for the transport of tissue samples. Theinner surfaces of cutter 100 and tube 152 may be coated with ahydrolubricous material to aid in the proximal transport of the excisedtissue samples.

A lateral extension 158 can be provided and can be supported by andextend distally from rear tube 152 for securing the tube to drivecarriage 134. The extension 158 connects tube 152 to carriage 134 sothat tube 152 translates with cutter 100, and maintains lumens 104, 156in continuous fluid-tight communication throughout the cutting cycle.

FIGS. 5 a-5 d provide simplified schematic views of the movement ofcutter 100 during a cutting cycle. As shown in FIG. 5 a, initially inthe cutting cycle cutter 100 is located at a proximal most position withdistal cutting end 106 disposed proximally of the proximal most edge ofthe side tissue port 86, and adjacent the proximal end of a lumendivider 170. As the cutting cycle begins, a lateral vacuum force(indicated by arrow 176) can be provided in lower lumen 84. Vacuum force176 can be transmitted from vacuum source 36 through tube 40 to lowerlumen 84 through a flow path provided by union sleeve 92.

Microprocessor 49 can be employed to activate valve 48 to supply vacuumforce 176 when switch 64 is actuated by the user to begin moving cutter100 distally within needle 80. Lateral vacuum force 176 communicateswith tissue receiving port 86 through fluid passageways 172 disposedunder port 86, and through one or more fluid passageways 174 disposeddistally of the port 86. In FIG. 5 c, a fluid passageway 174A isillustrated disposed distally of port 86 and spaced approximately 180degrees circumferentially from port 86. In FIG. 5 d, a fluid passageway174B is illustrated disposed distally of the port 86 in the distalendpiece 90 of the biopsy probe. Both fluid passageways 174A and 174Bcan provide fluid communication between lower lumen 84 and upper lumen83.

Lateral vacuum force 176 can be employed in combination with an axialvacuum force 180 through cutter lumen 104 to draw a tissue sample 182into tissue port 86. After tissue sample 182 is drawn into port 86,cutter 100 can be rotated and simultaneously translated distally tosever the tissue sample from the surrounding tissue. While cutter 100advances, vacuum forces 176, 180 can be maintained through lower lumen84 and cutter lumen 104 to draw the tissue sample into the cutter lumenas the sample is severed. As shown in FIG. 5 b, as cutter 100 advancesthe cutter slides across fluid passageways 172, successively blockingthe lateral vacuum through the holes.

When cutter 100 reaches the distal most position, as shown in FIG. 5 c,fluid passageways 172 can be completely blocked by the cutter. At thispoint in the cutting cycle, cutter rotation can be maintained, and thecutter can “freewheel” as described above, with the distal end 106 ofthe cutter 100 moving proximally and distally in an alternating,oscillating manner. As cutter 100 freewheels, the cutter can oscillatedistally and proximally a distance which can be about equal to the pitchof lead screw thread 144 at a frequency corresponding approximately tothe rotation speed of translation shaft 142. One or more fluidpassageways 174A can be positioned in lumen divider 170 such that ascutter 100 is freewheeling at its distal most position, the cutteralternately covers and uncovers (and so opens and closes) thepassageways 174A. With passageway 174A open, lower lumen 84 remains influid communication with cutter lumen 104 through divider 170 despitethe blocking of passageways 172. The repetitive movement of cutter 100over passageway 174A can assist in clearing any tissue that may beblocking or clogging passageway 174A, and to maintain fluidcommunication through passageway 174A.

Fluid Passageway 174B in distal endpiece 90 can be employed in place ofor in combination with fluid passageway 174A. Fluid passageway 174B canprovide fluid communication between lower lumen 84 and upper lumen 83when passageway 174 is covered by cutter 100.

A predefined amount of time after the cutter 100 reaches its distal mostposition and begins to freewheel, the solenoid on rotary valve 48 can bedeenergized or otherwise controlled by microprocessor 49 to replacelateral vacuum force 176 with forward pressurized air (eitheratmospheric or greater) as shown by the arrows in FIG. 5 c. Thepressurized air is discharged through lateral tube 40 to lumen 84. Withport holes 172 closed off by cutter 100, the pressurized aircommunicates with upper lumen 83 through fluid passageway 174A (and/or a174B) to apply a force against the distal face of sample 182. The forceacting on the distal face of sample 182 can act in combination with anwith axial vacuum force 180 provided through the lumen 104 of cutter100. The push provided by the force acting on the distal face of thesample 182 in combination with the vacuum “pull” provided by the vacuumprovided via the lumen 104 of cutter 100 can be employed to move thesample 182 into and through lumen 104 of cutter 100, as shown in FIG. 5d. Alternatively, instead of employing pressurized air to provide aforce on the distal face of sample 182, a pressurized liquid, such assaline, can be directed through lower lumen 84 and fluid passageways174A and/or 174B to provide the force on the distal face of sample 182.The cutter 100 closes the side tissue port 86 from the flow of fluid(gas or liquid) so that tissue surrounding the outer cannula and sideport 86 is not exposed to the fluid.

As the tissue sample 182 translates proximally through probe assembly 32towards sample collection assembly 52, the cutter 100 can be maintainedin a distal most position. Alternatively, the cutter 100 can beretracted back through tissue port 86 towards its initial position inpreparation for the next cutting cycle. After cutter 100 is fullyretracted, and the tissue sample is translated to tissue storageassembly 52, lateral vacuum force 176 is again provided via lumen 84 todraw the next tissue sample into port 86. During the translation ofcutter 100, the cutter can operate in conjunction with divider 170 toseparate lumen 83 from lumen 84.

During the cutting cycle, cutter 100 translates from a point justproximal of side tissue receiving port 86 to a point just distal of thereceiving port. The severed tissue samples are directed through thelength of the lumen 104 of cutter 100 and out of the proximal end of thecutter 100, rather than translating the cutter (with the samples carriedin the distal end of the cutter) proximally through the needle 80 toeject the samples with a knock-out pin, as in some prior devices.Accordingly, the cutting stroke length can be reduced to be justslightly longer than the length of the side tissue port 86. With thereduced stroke length, the distal end of the cutter 100 (as well as alength of the cutter 100) can remain within needle 80 throughout thecutting cycle, eliminating the need to accommodate the full length ofthe cutter within the probe housing and proximal of the needle 80. Inaddition, the reduced cutting stroke length reduces the required lengthof translation shaft 142, since the shaft need only translate the cuttera distance slightly longer than the length of tissue receiving port 86.Reducing the translation shaft length, and eliminating the need toaccommodate the cutter length within the probe housing, enables thelength of handpiece 30 to be reduced. The time to acquire each tissuesample is also reduced in the present invention, due to the shortenedcutting stroke reducing the time required to advance and retract thecutter through needle 80. Since cutter 100 retracts only to a point justproximal of tissue receiving port 86, lumen divider 170 can be formed toextend to the proximal most point of the cutter, rather than through theentire length of the needle. Reducing the length of divider 170 reducesthe required materials and cost of manufacturing needle 80.

As described above, fluid passageways 174A and/or 174B can also be usedto apply saline to the distal face of a severed tissue sample, such asillustrated in FIGS. 5C-D. The saline may be used to provide a pushagainst the tissue sample and thereby aid in moving the tissue sampleproximally within the cutter lumen 104. To provide a saline flush,tubing from saline supply bag 50 is routed through rotary valve 51 bycontrol module 46 to Y connector 44 and through lateral tube 40 to lumen84. In one embodiment, a button can be provided on handpiece 30, suchthat when the button is depressed while the cutter is freewheeling inits distal most position, the valve 51 is activated to connect thesaline 50 to lateral tube 40. Prior to a sampling procedure, the salinesystem may be primed by activating the rotary valve 51 to allow thevacuum from vacuum source 36 to draw saline into tubing 188. Saline willthen fill tubing 188 up to Y connector 44. When the operator thendepresses the handpiece button during the procedure, the saline willflow from Y connector 44, through lateral tube 40, and into lumen 84 tobe applied against tissue sample 182. When rotary valve 51 isdeenergized, tubing 188 is sealed off so that the flow of saline tolumen 84 is stopped.

In an alternative embodiment, saline can be automatically provided tolumen 84 during every cutting cycle. In this embodiment, a handpiecebutton is not required to operate the saline. Rather, microprocessor 49automatically activates rotary valve 51 a designated time after cutter100 reaches the distal most position within needle 80 during the cuttingcycle, and deactivates the valve when the cutter has retracted to adesignated proximal position. A position sensor can be incorporated withthe holster 34 or control module 46 to activate rotary valve 51 basedupon the axial position of the cutter in the cutting cycle. Thus, theposition of the cutter 100 will automatically activate and deactivaterotary valve 51, such as when the cutter advances and retracts duringeach cutting cycle.

As shown in FIG. 4, a drive slot 132 may be formed in proximal end 124of shaft 114 for interfacing with a similar-shaped drive slot in a motordrive shaft, or other rotary drive input from holster 34. Alternatively,as shown in FIG. 6, a star-shaped interface 130 may be molded intosecond axial end 124 of drive shaft 114. Star interface 130 can beprovided to mate with a similar-shaped male interface which could beprovided on the rotary drive shaft of holster 34 to rotate drive shaft114. Alternatively, the female star interface 130 may be molded into thedrive shaft from holster 34 and a similar-shaped male interface formedin drive shaft 114. Use of star interface 130, or another similar typeof interface that is molded into the rotary drive shaft, minimizes theaxial length required for the drive coupling. Reducing the drivecoupling length reduces the overall length of probe 32.

FIGS. 7 and 8 illustrate an alternative embodiment for the invention, inwhich cutter 100 and rear tube 152 are releasable from probe assembly 32such that the cutter 100 can be repeatedly removed and re-inserted intothe probe assembly 32 without disassembling the probe assembly 32.Removal (either partial or complete removal) of the cutter 100 can beadvantageous, such as where the cutter 100 is formed of metal and theimaging device employed with the probe 32 is a Magnetic ResonanceImaging (MRI) device. In FIGS. 7 and 8, the proximal portion of reartube 152 is not shown.

In the embodiment shown in FIGS. 7 and 8, cutter 100 and rear tube 152can be joined at a seal 154 just proximal of cutter gear 110, such thatthe cutter is capable of rotating relative to the rear tube 152 (whichcan be supported to not rotate). A cutter release lever 160 can besupported on and can protrude from rear tube 152. Release lever 160 asshown includes an end 162 extending distally towards carriage 134. Alateral slot 164 in end 162 is shaped and sized to engage a featureassociated with carriage 134, such as a disk feature 166 which can besecurely attached to a proximal hook extension 140 of carriage 134.While slot 164 engages disk 166, cutter 100 and rear tube 152 translatetogether with carriage 134. A spline features 168 located near theproximal end of cutter 100 can be employed to engage with acomplimenting spline feature on the internal diameter of cutter gear 110to insure the cutter 100 and cutter gear 110 rotate together.

To remove cutter 100 and tube 152 from probe assembly 32, such as forimaging prior to a cutting cycle, the proximal end of release lever 160is squeezed in the direction of tube 152. The squeezing action unlatchesslot 164 from disk 166, releasing cutter 100 and tube 152 from both thecarriage 134 and the cutter gear 110. As shown in FIG. 8, after tube 152and cutter 100 are released, the tube and cutter may be pulledproximally through the cutter gear bore and out the proximal end ofprobe assembly 32. To reinsert cutter 100 and tube 152, the tube andcutter are connected at seal 154, and the combination is insertedthrough the proximal end of probe assembly 32 so that the cutter againextends through the cutter gear bore and union sleeve bore 94 intocannula 82. Cutter 100 and tube 152 are pushed distally through probeassembly 32 until slot 164 of end 162 again latches onto disk 166.

The cutter 100 may be repeatedly removed from and reinserted into theprobe assembly 32 through an opening in the proximal end of the probeassembly 32. The tissue receiving port 86 can be positioned in tissue tobe sampled, the cutter 100 can be removed from the probe assembly 32,the biopsy site can be imaged, such as by using MRI, the cutter can beinserted into the probe assembly 32, and the tissue received in the sidetissue port 86 can be severed with the cutter 100. The step of removingthe cutter from the probe assembly can be performed before or after thetissue port 86 is positioned within the tissue to be sampled.Additionally, the cutter can be removed after a tissue sample issevered, either before or after the needle 80 is removed from tissue.

As shown in FIGS. 9 a and 9 b, a divider 170 may be inserted in thedistal end of cannula 82 to separate the interior of needle 80 intoupper and lower lumens 83/84. In the embodiment shown in FIGS. 9 a and 9b, divider 170 extends axially through cannula 82 to a point justproximal of tissue receiving port 86. The proximal end of divider 170can coincide with the proximal most position of cutter 100 so that thecutter and divider combine to separate the upper and lower lumens.Alternatively, divider 170 could extend axially through the full lengthof needle 80. As shown in FIG. 9 a, divider 170 can comprise a curvedsurface that conforms closely to the outer circumference of cutter 100to enable the cutter to slide along the surface of the divider as thecutter translates within cannula 82. A plurality of fluid passagewayholes 172 can be formed in divider 170 beneath tissue receiving port 86(spaced approximately 180 degrees from the port 86). Fluid passageways172 can be sized to permit fluid communication between lumens 83 and 84(and tissue receiving port 86), while preventing excised tissue portionsfrom passing into the lumen. Divider 170 can also include one or morefluid passageways 174 distal of the tissue receiving port 86 throughwhich compressed gas (e.g. air) or liquid (e.g. saline) can be providedto the distal face of a tissue sample located within the cutter lumen104 while the cutter 100 is in its distal most position closing off thetissue receiving port 86. With cutter 100 in the distal most positionand closing off the tissue receiving port 86, tissue samples can bepushed through the cutter 100 without exposing tissue surrounding thecannula 82 to the fluid. Divider 170 may be formed of the same materialas cannula 82, and the longitudinal edge of the divider may be welded orotherwise permanently affixed to the inner diameter of the cannula.

FIGS. 10 and 11 illustrate an alternative embodiment for a biopsy needlesuitable for use with a probe assembly 32. The needle, designated bynumeral 165, can be assembled from an aperture component, a tissuepiercing component, and a tube component. In this embodiment, tubecomponent 168 comprises a cannula 171 having a lumen 173 extending therethrough, and a tissue receiving aperture 175 adjacent the distal end ofthe tube. The aperture component 177 comprises an aperture 178 and fluidpassageways 179. The tissue piercing component component 90 can beinsert molded into the aperture component or mechanically secured to it,such as with adhesive or other suitable bonding means.

As shown in greater detail in FIGS. 12 and 13, aperture component 177can have a semi-tubular shape with an upper opening 178 of substantiallythe same length as tissue receiving aperture 175. Opening 178 alignswith tissue receiving aperture 175 when the two components 168, 177 areassembled together. A plurality of fluid passageways 179 are formed in alower surface 169 of aperture component 177 beneath opening 178. Lowersurface 169 can provide a divider for providing a lower lumen whenneedle 165 is assembled. One or more fluid passageways 181 can beprovided distal of opening 178 so as to be distal of tissue receivingaperture 175 when the needle components are assembled together.Passageways 179 and 181 provide flow communication for compressed fluid(e.g. air and/or saline) from the lower lumen to the upper lumen whenneedle components 168, 177 are assembled together. A pair of engagementbosses 183 can be provided and can extend from the proximal end ofaperture component 177 for attaching the aperture component to tubecomponent 168. To assemble needle 165, aperture component 177 isinserted through the distal end of cannula 171 until bosses 183 engagecomplimentary grooves or holes on the inner diameter of the tubecomponent 168. The engagement between the bosses and grooves locksaperture component 177 within tube component 168. In addition, whenneedle 165 is assembled into probe assembly 32, the portion of thecutter 100 which extends distally beyond bosses 183 in tube component168 can further prevent the aperture component 177 from disengaging formthe tube component 168. A circumferential lip 185 can be provided on theaperture component 177. The lip 185 can provide a seating surface forthe distal end of tube component 168 when the aperture component isassembled with the tube component.

Referring again to FIG. 5, once a tissue sample enters the lumen 104 ofcutter 100, the axial vacuum force 180 can serve to pull the sampleproximally through the cutter 100 to be directed from probe assembly 32into tissue storage assembly 52. In a first embodiment, tissue storageassembly 52 comprises a serial tissue stacking assembly 190, such as isshown in FIG. 14. In serial tissue stacking assembly 190, multipletissue samples are stacked one behind the next in an end to endconfiguration, such as in a flexible tube. The samples may be removedindividually from the tube and examined in real-time during theprocedure or, alternatively, left in the tube until the end of theprocedure and removed all at once. The distal end of serial tissueassembly 190 can be detachably connected via dual connection mechanismsto probe assembly 32 (so that the serial tissue storage assembly 190 isreleasable from the probe assembly), while the proximal end of theassembly 190 can be detachably connected via tube 42 to a vacuum source,such as vacuum source 36 shown in FIG. 1.

In the embodiment shown in FIGS. 15 a and 15 b, an upper connector 192at the distal end of serial tissue assembly 190 includes a pair of snapfasteners 194. Fasteners 194 engage a pair of fastener engaging features196 that are disposed at the proximal end of the probe assembly, such asa pair of notches that can be formed in a portion of the proximal end ofprobe lower shell 72. When fasteners 194 are engaged with features 196,as shown in FIG. 15 a, the upper portion of serial tissue assembly 190is attached to the probe housing.

A second, lower connecter 198, also at the distal end of serial tissueassembly 190, can include a similar pair of snap fasteners 200. Lowersnap fasteners 200 engage a mating pair of features 202 on the proximalend of the rear tube 152 that is shown extending from a proximal openingin probe assembly 32 in FIG. 15 b. The distal end of rear tube 152 canbe joined to carriage 134 as shown in FIG. 8. When lower snap fasteners200 engage notches 202, as shown in FIG. 15 b, the lower portion ofserial tissue assembly 190 moves distally and proximally with thetranslation of drive carriage 134. When both upper connector 192 andlower connector 198 are attached to probe assembly 32, the lower portionof serial tissue assembly 190 will translate relative to the fixed upperportion of the assembly during the cutting cycle. To detach serialtissue assembly 190 from probe assembly 32, each of the pairs of snapfasteners 194, 200 are pushed inwardly at the distal ends to disengagethe forward tips of the fasteners from the corresponding notches 196,202. After the fasteners are disengaged, serial tissue assembly 190 maybe separated from probe assembly 32.

As shown in FIGS. 14 and 16, serial tissue assembly 190 includes asample storage tube 206 having dual lumens extending axiallytherethrough. The dual lumens can be generally parallel. Tube 206 may becomprised of polyvinyl chloride or another similar type of flexible,water insoluble material. Using a clear material for storage tube 206,such as polyvinyl chloride, enables the stacked tissue samples to bevisible from outside the tube.

Tube 206 can include a longitudinally extending center wall divider forseparating the two lumens. Tube 206 can comprise a first lumen, such asstacking lumen 210, for transferring and storing tissue samples 204 thathave been aspirated to the assembly through cutter lumen 104. Tissuestacking lumen 210 can be detachably connected to the proximal end ofrear tube 152 by lower connector 198. When fasteners 200 engage features202, as described above, tissue stacking lumen 210 can be axiallyaligned with rear tube lumen 156 to provide a continuous, unobstructedpassageway for the movement of tissue samples 204 from tissue receivingport 86 into the tissue lumen stacking lumen 210.

As tissue samples 204 enter tissue stacking lumen 210, the samples stackserially one behind the next within the lumen, in end to endconfiguration, as shown in FIG. 16, so that the order of the samples(the order in which the samples are obtained from the biopsy site) ismaintained while the samples are stored in tissue stacking lumen 210. Atissue stop can be located within the tissue retrieval mechanism 260 atthe proximal end of tissue lumen 210 to prevent the first or earliestsample from translating completely through the tissue lumen and intovacuum system 36. The tube 206 can comprise a second lumen, tissuestacking vacuum lumen 214, for providing a flow communication path forvacuum through rear tube 152 and cutter 100 so that severed tissuesamples 204 can be drawn through cutter 100 and rear tube 152 intotissue stacking lumen 210. The proximal end of tissue stacking vacuumlumen 214 can be detachably connected to vacuum source 36 through alateral attachment port 216.

As shown in greater detail in FIG. 17, a plurality of small holes 220can be provided in the center wall divider of tube 206 between lumen 214and lumen 210 to provide flow communication between the lumens. Holes220 enable vacuum from source 36 to be communicated from lumen 214 intolumen 210, to provide vacuum in lumen 104 of cutter 100. Holes 220 arepreferably spaced along the longitudinal axis of tube 206 and separatedby a distance in the range of 0.1 to 4 centimeters. Holes 220 may beoriented at an angle relative to the longitudinal axis of tube 206. Theangle in holes 220 can function as a mechanical diode, in that the edgeof the holes 220 opening into lumen 210 can aid in preventing motion oftissue samples in a distal direction, while permitting tissue samples tomove proximally in lumen 210 under vacuum force provided by vacuumsource 36. A tissue sample will continue to slide proximally through thelumen 210 until the sample contacts either the tissue stop within thetissue retrieval mechanism 260 or a preceding tissue sample.

Vacuum holes 220 may be formed between lumens 210, 214 by boring intothe upper surface of tube 206 with the sharpened tip of a drill or otherappropriate instrument. The tip of the drill bit or other boringinstrument can be directed to pass through vacuum lumen 214 to penetratethe center wall of tube 206 that separates the two lumens. As shown inFIG. 14, an outer sleeve 228 is securely attached to the surface of tube206 following the formation of vacuum communication holes 220. Outersleeve 228 may be attached to tube 206 by an adhesive or otherappropriate type of attachment mechanism. Outer sleeve 228 is attachedto sample tube 206 over the openings used to form vacuum communicationholes 220 to seal the openings, and prevent vacuum from passing out ofvacuum lumen 214 through the openings. The distal end of outer sleeve228 can be formed to extend beyond the distal end of vacuum lumen 214 toconnect with upper connector 192. Vacuum lumen 214 attaches to probeassembly 32 through the connection between outer sleeve 228 and upperconnector 192.

As tissue samples 204 are stored in lumen 210, the stack of samples 204will grow in length distally in lumen 210. The samples 204 will tend toblock or otherwise restrict flow communication through vacuum holes 220as the stack of samples extends distally in lumen 210. In FIG. 16, atranslating flexible rod 230 is shown disposed at least partially inlumen 214. Rod 230 can extend axially through lumen 214 to selectivelycover or otherwise block at least some of the vacuum holes 220. Rod 230can then be manipulated, such as by axial movement of rod 230, toselectively expose vacuum holes 220 in the vacuum lumen. For instance,during each cutting cycle, rod 230 can be advanced distally withinvacuum lumen 214 to expose or otherwise unblock/open additional vacuumholes 220 as additional samples are stored in lumen 210. The movement ofrod 230 maintains a predetermined number of vacuum holes 220 open toprovide flow communication between lumens 210 and 214 as additionaltissue samples are added to the stack of tissue samples in lumen 210.This can aid in providing a consistent vacuum force in cutter lumen 104throughout multiple cutting cycles. Initially, flexible rod 230 can beinserted within lumen 214 such that rod 230 is axially offset withinlumen 214 so as to cover or otherwise block most, but not all, of theholes 220. For instance, prior to storing any samples in lumen 214, rod230 can be offset distally within vacuum lumen 214 a distance that isslightly longer than the length of tissue receiving port 86. Offsettingrod 230 distally within lumen 210 ensures an initial set of holes 220are exposed to communicate axial vacuum force 180 to tissue receivingport 86 when cutter 100 is in the fully proximal position prior totissue sampling. The axial vacuum force communicated through the exposedholes 220 aids in prolapsing tissue into receiving port 86 prior tocutting, as well as pulling the tissue sample proximally into tissuelumen 210 after cutting. As a tissue sample is drawn into and stackedwithin tissue lumen 210, the tissue sample blocks the previously exposedvacuum holes 220, preventing vacuum from passing into the tissue lumen.Rod 230 can be selectively moved a predetermined distance distally thatis slightly longer than the length of tissue receiving port 86 to exposeadditional vacuum holes 220 immediately distal of the most recentlyacquired tissue sample. Rod 230 can be adapted to be automaticallyadvanced distally by the translation of drive carriage 134 within probeassembly 32, as described further below. The newly exposed vacuum holes220 continue the communication of vacuum force 180 into tissue lumen 210for the next cutting cycle.

Rod 230 can be formed of a fluoropolymer resin material such as Teflon®or other suitable flexible material having a low coefficient offriction. Rod 230 can be sized and shaped to conform closely to theinner diameter of vacuum lumen 214. The close fit between rod 230 andvacuum lumen 214, as well as the low friction properties of the rod,enable the rod to translate easily within the vacuum lumen without anyloss of vacuum force through the distal end of the lumen.

The distal end 231 of rod 230 extends outside of vacuum lumen 214through an opening 234 in outer sleeve 228. As rod 230 is advanceddistally, the rod moves further out of vacuum lumen 214 through opening234. The flexibility of rod 230 allows the rod to flex out of opening234 in outer sleeve 228 as the rod is continually advanced distally,enabling substantially the entire rod to be translated out of vacuumlumen 214 over the course of multiple cutting cycles. As shown ingreater detail in FIG. 18, rod 230 can include a plurality of sideratchet teeth 232 spaced longitudinally substantially along the lengthof the rod. Teeth 232 provide a mechanism to grip and advance rod 230through vacuum lumen 214. Rod 230 can also include a plurality of bottomratchet teeth 238.

Rod 230 can be advanced distally within vacuum lumen 214 by theinteraction between teeth 232 and a pawl-type latching mechanism 240 ona reciprocating member 242, which is shown in greater detail in FIG. 19.Reciprocating member 242 can be supported on lower connector 198 andreciprocates as cutter 100 is advanced and retracted. Reciprocatingmember 242 can have a bifurcated proximal end with proximally extendingportions 243 separated by an axially extending slot 244. A rampedsurface 246 can be formed between portions 243 at a distal end of slot244. Ramped surface 246 can serve to deflect the distal end 231 of rod230 through opening 234 and alongside the outer surface of tube 206 asthe rod is ratcheted out of vacuum lumen 214. Unidirectional engagementpawls 250 can be formed to extend from the sides of portions 243 facingslot 244 to engage side ratchet teeth 232 on rod 230 as the rod extendsthrough the groove. The engagement between pawls 250 and ratchet teeth232 advances rod 230 distally through vacuum lumen 214.

The distal end of reciprocating member 242 can be fixed to lowerconnector 198 for translation along with the lower connector 198,carriage 134, and cutter 100 during each cutting cycle. As drivecarriage 134 advances distally at the beginning of a cutting cycle tomove cutter 100 into receiving port 86, reciprocating member 242 alsoadvances distally. As reciprocating member 242 advances, pawls 250 ingroove 244 engage side teeth 232 on rod 230 in lumen 214 to pull the roddistally with the reciprocating member. As rod 230 moves distally withinlumen 214, additional vacuum holes 220 are exposed. As the direction ofcarriage 134 reverses, and cutter 100 retracts from receiving port 86,reciprocating member 242 moves in a proximal direction relative to thefixed vacuum lumen 214. As reciprocating member 242 retracts proximally,unidirectional bottom ratchet teeth 238 located on the bottom side offlexible rod 230 engage vacuum holes 220 within vacuum lumen 214 asshown in FIG. 17. The engagement between the ratchet teeth and holes 220prevents rod 230 from moving proximally within vacuum lumen 214. Aspawls 250 move proximally relative to rod 230, the pawls engage the nextproximal set of ratchet teeth 232 on rod 230. This engagement with thenext set of ratchet teeth 232 causes rod 230 to again advance distallywhen drive carriage 134 advances distally during the next cutting cycleto expose additional vacuum communication holes 220. In the event thatthe carriage and cutter assembly is advanced and retracted without theprobe assembly 32 in tissue, resulting in the flexible rod 230 advancedtoo far distally relative to the tissue samples 204; the flexible rod230 can be rotated a fraction of a turn about its longitudinal axis todisengage ratchet teeth 232 and 238 allowing the flexible rod 230 to berepositioned proximally within the vacuum lumen 214.

In an alternative embodiment not shown, flexible rod 230 could beadvanced distally within vacuum lumen 214 as drive carriage 134 isretracted proximally following the cutting of tissue. In thisembodiment, a reversing mechanism such as, for example, a cableextending 180° degrees around a pulley, could be utilized so that as thedrive carriage retracts the cable pulls the flexible rod distally.

As shown in FIG. 19, lower connector 198 includes an axially-extendingbore 252 for connecting the tissue lumen portion of sample tube 206 torear tube 152. When serial tissue assembly 190 is connected to probeassembly 32 by lower connector 198, tissue lumen 210, bore 252, and reartube lumen 156 are aligned generally coaxially to provide anunobstructed passageway for the aspiration of tissue samples from cutter110 and rear tube 152 to lumen 210.

FIG. 20 illustrates in greater detail connectors 192, 198 and lumens210, 214. As shown in FIG. 20, vacuum lumen 214 can be attached to fixedupper connector 192 by outer sleeve 228. Vacuum lumen 214 thus remainsfixed in position within serial tissue assembly 190 throughout thecutting cycle. Tissue lumen 210 extends distally into bore 252 of lowerconnector 198. At least a distal portion of tissue lumen 210 willtranslate along with lower connector 198 and drive carriage 134 duringeach cutting cycle. As drive carriage 134 and lower connector 198translates proximally, a distal portion 211 of the sample tube includingthe distal portion of tissue lumen 210 flexes or otherwise deformsdownward, enabling the distal end of the tissue lumen to translate alongwith lower connector 198 and reciprocating member 242, while vacuumlumen 214 remains fixed in position by outer sleeve 228.

As shown in FIGS. 14 and 16 a tissue retrieval mechanism 260 may belocated at the proximal end of serial tissue assembly 190 for removingsamples from the assembly in real-time following each cutting cycle.Tissue retrieval mechanism 260 can be is positioned in relation tosample tube 206 just distal of tissue stop 212 (FIG. 23). As shown ingreater detail in FIGS. 21, 22, and 23, tissue retrieval mechanism 260includes a retractable outer sleeve 262. Outer sleeve 262 ispneumatically sealed by o-rings 263 to maintain vacuum within sampletube 206 during the cutting cycle. To remove a tissue sample from tube206 following a cutting cycle, outer sleeve 262 is manually rotated ortranslated out of position using pull-tab 270 to expose the tissuesample in tissue lumen 210. A tissue retrieval window 264 can be formedin tissue lumen 210 beneath outer sleeve 262 to provide access to thetissue sample in the lumen once the outer sleeve is retracted. An airinlet 265 can be located distal of tissue retrieval window 264 to applyair pressure to the distal face of the tissue sample 204 in the window,to prevent distal movement of the sample when outer sleeve 262 isretracted due to a pressure imbalance on tissue sample 204. A lowercylinder 266 on retractable sleeve 262 can house a return spring 258 forbiasing the sleeve into the closed, sealed position. Each end of thespring 258 is secured to the retrieval mechanism 260 with pins 224. Theproximal end of tissue retrieval assembly 260 can include a vacuumattachment 268 for providing vacuum to tissue lumen 210, such as fromvacuum source 36. Vacuum attachment port 216 can also be provided toextend through retrieval mechanism 260 to provide vacuum to lumen 214,such as from vacuum source 36. At the end of a procedure, tissueretrieval assembly 260 may be disconnected from sample tube 206 so thattissue samples may be retrieved from the tube, as will be described infurther detail below.

As an alternative or in combination with real-time sample retrievalthrough tissue retrieval assembly 260, tissue samples may be retrievedat the end of a procedure by disconnecting sample tube 206 from probeassembly 32 and removing tissue retrieval assembly 260 from the proximalend of tissue lumen 210. After sample tube 206 is disconnected, a samplereleasing mechanism such as, for example, the flexible rod such asplunger-like component 278 shown in FIG. 24, may be inserted in one endof tissue lumen 210 and advanced there through to extract the samplesfrom the opposite end of the lumen as shown in FIG. 25. Alternatively,the tissue sample tube may be formed such that vacuum lumen 214 isseparable from tissue lumen 210 at the conclusion of the procedure toallow access to the tissue samples stacked within the tissue lumen.

FIGS. 26 a-26 c illustrate one embodiment for a separable sample storagetube in which a dual lumen tube 280 is extruded with weakened sidesalong the exterior of tissue lumen 210, as indicated by referencenumeral 282, so that a portion of the lumen 210 is separable, such as bypeeling, to expose tissue samples. When opposite forces are applied tolumens 210, 214, the two lumens can be peeled apart at the weak points282, with the upper portion of tissue lumen 210 separating with vacuumlumen 214 as shown in FIG. 26 b. The remaining, lower portion of tissuelumen 210 will form an open U-channel containing the stacked tissuesamples (U-channel shown in FIG. 26 c). The samples may be removed fromthe opened tissue lumen 210 using a forceps or other instrument.

As an alternative to extruding the sample tube with weakened side points282, tissue and vacuum lumens 210, 214 could be extruded separately andassembled together to form a dual lumen tube 284, an example of which isshown in FIG. 27 a. In this embodiment, vacuum lumen 214 is extruded toinclude the upper portion of tissue lumen 210 so that tissue lumen 210forms an open U-channel. The tissue and vacuum lumens 210, 214 arejoined along the upper edges 286 of the U-channel by an adhesive orother type of fastening mechanism. To access the tissue samples,opposite forces are applied to tube 284 to break the adhesive bond orother fastening means and peel vacuum lumen 214 away from tissue lumen210, as shown in FIG. 27 b. The samples may then be removed from theopen tissue lumen.

In yet another embodiment for a separable sample storage tube, shown inFIG. 28, a dual lumen tube 290 is formed by joining separately extrudedvacuum and tissue lumens 210, 214. In this embodiment, vacuum lumen 214is formed as a closed piece having at least one pair of laterallyextending teeth 292. Tissue lumen 210 is formed as an open U-shapedchannel having a corresponding number of pairs of laterally extendingnotches 294 along the inner surfaces of the channel. Teeth 292 areshaped to engage notches 294 to form a mechanical latch 296 that locksvacuum lumen 214 and tissue lumen 210 together to form the sample tube.Pulling vacuum lumen 214 in an opposite direction away from tissue lumen210 will disengage teeth 292 from notches 294, thereby opening the topof the tissue lumen to remove tissue samples. Mechanical latch 296 maybe used in combination with an adhesive or other attachment mechanism tolock the vacuum and tissue lumens together.

FIGS. 29 and 30 illustrate an alternative embodiment for serial tissuestacking assembly 190 where sample storage tube 206 is replaced with aseparable sample storage tube shown in FIGS. 26-28. In addition, thetissue retrieval mechanism 260 is replaced with a tissue lumen peel tab272. A tissue stop feature is located in lumen peel tab 272 at theproximal end of tissue lumen 210. A tubing connector 274 connects theproximal end of vacuum lumen 214 to an axial vacuum line, such as avacuum line 42 communicating with vacuum source 36. In this embodiment,tissue samples are stacked distally from the tissue stop. The tissuesamples 204 can be removed real time by peeling the tissue lumen fromthe vacuum lumen 214. Alternately, the tissue samples can be removed atthe conclusion of the procedure.

FIGS. 31 a-31 d illustrate the advanced and retracted positions of lowerconnector 198, tissue lumen 210 and rod 230 for the initial two cuttingcycles of a biopsy procedure. As shown in FIG. 31 a, when cutter 100 isadvanced to a fully distal position, i.e. completely through tissuereceiving port 86, tissue lumen 210 is advanced fully distal as well,with the tissue lumen substantially parallel to outer sleeve 228. Ascutter 100 retracts from tissue receiving port 86 following tissuecutting, tissue lumen 210 retracts with drive carriage 134 to a proximalposition, as shown in FIG. 31 b. In this position, the a distal lengthtissue lumen 210 extends downward, such as by flexing, away from outersleeve 228. Reciprocating member 242 also retracts and grips the nextset of ratchet teeth 232 on rod 230. During the next cutting cycle,shown in FIG. 31 c, cutter 100 is again fully advanced by drive carriage134 and lower connector 198 again pulls tissue lumen 210 distally. Aslower connector 198 is pulled distally, engagement pawls 250 pull onratchet teeth 232 of rod 230 to advance the rod through vacuum lumen 214and out opening 234. At the conclusion of the second cutting cycle,tissue lumen 210 is again retracted proximally as shown in FIG. 31 d.

FIG. 32 illustrates an alternative embodiment for tissue storageassembly 52, in which the storage assembly comprises a parallel tissuestacking assembly 300. In parallel tissue stacking assembly 300, tissuesamples are stored one beside the next in a tissue storage component andremoved at the end of the procedure. As shown in FIGS. 32 and 33,parallel stacking assembly 300 comprises a tissue storage component 302containing a series of side-by-side lumens 304. Each of the lumens 304is slightly longer than the length of tissue receiving port 86 forstoring tissue samples aspirated from the receiving port. Component 302may be comprised of a clear plastic material to allow visual inspectionof the tissues samples stored therein. An integrated knock-out pin 306,(FIG. 34), can be provided at the proximal end of each tissue lumen 304to prevent tissue samples from translating completely through the lumenand into vacuum system 36, while providing vacuum to be communicated toa lumen (eg. each knockout pin 306 can include a small central openinglarge enough to provide flow communication for providing vacuum to lumen304, but small enough to not allow a tissue sample to pass out thedistal end of lumen 304.)

Returning to FIGS. 32 and 33, a tissue tube 308 having a tissue lumen310 therein, extends distal of component 302 to connect with tube 152 inprobe 32. Tubes 152 and 308 can be aligned to provide a continuous,generally straight line passageway from lumen 104 of cutter 100 to alumen 304 in component 302. An O-ring seal 312, shown in FIG. 35, can beprovided at the proximal end of tissue tube 308 to seal the passagewaybetween tissue lumen 310 and the lumen 304 aligned with tube 308. Sampleand tissue tubes 152, 308 may be detachably connected by any suitabletype of fastening mechanism such as, for example, snap fasteners similarto those shown in FIGS. 15 a and 15 b. A first vacuum port 314 can belocated on the proximal side of component 302 to provide vacuum totissue lumen 310 through the lumen 304 aligned with tube 308. A secondlateral vacuum port 316 can be employed to provide vacuum to tissuelumen 310 at a position distal of component 302. Each of vacuum ports314, 316 can be attached to vacuum source 36 through an axial vacuumline 42 to provide vacuum for drawing tissue proximally in lumen 104 ofcutter 100. Lateral vacuum port 316 can be attached to a vacuum chamber320 that surrounds tissue tube 308. Tissue tube 308 can include aplurality of spaced holes within vacuum chamber 320 for communicatingvacuum between the chamber and tube lumen 310. Lateral vacuum port 316and chamber 320 provide additional vacuum for aiding in the proximalmovement of a tissue sample (such as in the case where a tissue samplefragments into multiple pieces during sampling).

After a tissue sample is stored in a lumen 304, component 302 can beindexed laterally to axially align the next adjacent lumen with tissuelumen 310. As shown in FIG. 33, a cam member 322 is provided forindexing component 302. Cam member 322 is located in a housing 324 thatextends beneath component 302. Cam member 322 is operatively connectedto drive carriage 134 in probe assembly 32 to translate distally andproximally with the drive carriage during each cutting cycle. Cam member322 is attached to drive carriage 134 by a mechanical cable 326 thatextends distally through an end cap 330. Cable 326 is attached to drivecarriage 134 and pulls cam member 322 distally as the drive carriage 134moves distally. As cam member 322 moves, a camming surface 332 on thecam member interacts with bosses 334 (shown in FIG. 34) on the undersurface of component 302 to index component 302. Camming surface 332 cancomprise an angled, flexible strip of material that is deflected bybosses 334. As shown in FIG. 36 a, camming surface 332 is in anon-deflected position between two bosses, identified by phantom bosses336, 338, when cam member 322 is in a proximal-most position prior to acutting cycle. As cam member 322 advances distally at the beginning of acutting cycle, camming surface 332 is deflected out of position by thecontact between boss 336 and a first side of the camming surface. As cammember 322 continues to advance distally, boss 336 deflects cammingsurface 332 to a point at which the boss passes through an openingcreated between the cam surface and a stop block 340, as shown in FIG.36 b. After boss 336 passes through the opening created by thedeflecting camming surface, the camming surface springs back into anon-deflected position in contact with stop block 340.

When drive carriage 134 begins to retract following the cutting oftissue, a return spring 224 within the distal end of housing 324 pushescam member 322 proximally within the housing. As cam member 322 retractsproximally, the opposite side of camming surface 332 contacts boss 336.As cam member 322 continues to retract, the angle in camming surface 332causes boss 336 to be pushed laterally, as shown in FIG. 36 c. As boss336 is pushed laterally, component 302 is indexed laterally relative totissue tube 308, thereby positioning the next adjacent lumen 304 toreceive the next tissue sample through tube 308. As shown in FIGS. 32and 33, component 302 is positioned between cam member housing 324 and adetent arm 342. Detent arm 342 extends distally across the upper surfaceof component 302. As component 302 is indexed laterally by theinteraction of camming surface 332 and boss 336, detent arm 342 engagesone of a series of indexing detents 344. Indexing detents 344 lock thenext active lumen 304 into alignment with lumen 310 following eachindexing action. The plurality of bosses 334 and indexing detents 344enable component 302 to be repetitively indexed to store a plurality oftissue samples during a biopsy procedure. At the conclusion of a biopsyprocedure, component 302 may be removed from between housing 324 anddetent arm 342, and the tissue samples removed from the individualtissue lumens 304. The top surface of component 302 can include a coveror other removable portion to allow each sample to be easily removedfrom the lumens 304.

FIG. 37 is an exploded isometric view of an exemplary drive assembly 350for holster 34. In the assembly shown in FIG. 37, the translation androtation drive trains (for providing rotation and translation of cutter100) are driven by a single rotatable cable 55 (also shown in FIG. 1)that extends between holster 34 and a remotely located motor, such as amotor in control module 46. A single drive cable is capable of rotatingboth drive trains due to the reduced cutter stroke of the presentinvention. The reduced cutter stroke enables the size of handpiece 30,as well as the load on the drive motor, to be reduced relative toprevious biopsy devices. Powering handpiece 30 through a singlerotatable cable enables the handpiece to be utilized in MRI guidedprocedures since ferromagnetic motor components are separated from thehandpiece. The handpiece can also be used in mammography and ultrasoundguided procedures. Accordingly, a common probe assembly and handpiececan be utilized for multiple imaging environments. For an MRI guidedprocedure, the length of the rotatable cable may be increased toaccommodate use near or within an MRI bore.

In the embodiment shown in FIG. 37, rotatable cable 55 attaches to adrive cable input coupling 352 for providing rotational drive to holster34. A drive shaft 354 from input coupling 352 extends to a proximalhousing 356. Within proximal housing 356, an input gear 360 is mountedon input drive shaft 354 between spacer 362 and bearing 389 so as toengage corresponding gears on a translation drive shaft 364 and arotation drive shaft 366. The interaction of the input gear 360 withtranslation shaft gear 370 and rotation shaft gear 372 transmits therotational drive to translation and rotation drive shafts 364, 366.Translation and rotation drive shafts 364, 366 extend from proximalhousing 356 through a pair of bores in a center housing 374. Translationand rotation gears 370, 372 are spaced between the proximal and centerhousings by bearings 376.

Distal of center housing 374, holster 34 includes a rotary encoder 380for providing a feedback signal to control module 46 regarding rotationof the drive shafts. Encoder 380 may be mounted on either thetranslation or the rotation drive shafts. Holster 34 also includes anoptional planetary gearbox 382 on translation drive shaft 364. Gearbox382 provides a gear reduction between the translation and rotation drivetrains to produce differing speeds for the translation of drive carriage134 and the rotation of cutter 104. Distal of gearbox 382 and encoder380, drive assembly 350 includes a housing 384. Housing 384 includesconnections for coupling the translation drive train with translationdrive input shaft 386, and the rotational drive train with rotary driveinput shaft 388. Each of the drive input shafts 386, 388 has a distalend shaped to operatively engage slots on corresponding drive shafts inprobe assembly 32. In particular, translation drive input shaft 386 isshaped to engage slot 128 of translation shaft 142 (shown in FIG. 4),and rotary drive input shaft 388 is shaped to engage slot 132 of rotarydrive shaft 114. As mentioned above with respect to FIG. 6, the driveinput shafts may have molded interfaces, rather than the mating slotsand tips shown in FIGS. 4 and 37, to reduce the coupling length betweenthe shafts. Translation and rotary drive shafts 386, 388 extend distallyfrom housing 384 for engagement with drive and translation shafts 114,142 when probe assembly 32 and holster 34 are connected.

The embodiment shown in FIG. 37 comprises a single drive cable input foroperatively driving the translation and rotation shafts. In analternative embodiment, a single motor mounted in the holster 34 canreplace rotatable cable 55. The single motor drives both the translationand rotation shafts through a suitable gearing assembly. The motor maybe mounted above or proximal to the drive assembly. Another embodimentreplaces the single motor with two motors. One motor would drive thetranslation drive input shaft and the other would drive the rotary driveinput shaft.

In the embodiments described, the cutting stroke length for the cutter100 is reduced to slightly longer than the length of tissue receivingport 86. This stroke reduction is possible in part because tissuesamples are aspirated through the cutter lumen, rather than being pulledproximally through the needle by a retracting cutter. Reducing thecutting stroke length has a number of benefits. One of the benefits of areduced cutting stroke length is that the overall size and weight of theprobe assembly may be reduced, thereby enabling the biopsy device to beused in imaging environments where size has traditionally been alimitation. In particular, the reduced size of the probe assemblyenables an essentially common probe assembly to be used in both open andclosed bore MRI guided procedures, as well as in mammography andultrasound procedures, with minor adjustments. A common cable drivenholster may also be used in each of the imaging modalities, with thealternative, single or double motor embodiments useable in both themammography and ultrasound guided procedures. In addition, a commoncontrol module can be used to control the handpiece in any of the threeimaging environments. The probe assembly may be adapted for use in anMRI guided procedure by utilizing a needle and cutter subassembly thatis comprised of a non-ferromagnetic material, such as a plastic orceramic, in order to reduce image artifacts. In addition, the cutterassembly may be removed from the probe, as described above with respectto FIGS. 7 and 8, for MRI imaging prior to initiation of a cuttingcycle. Alternately, the distal end of the cutter may be simply retractedproximally from the tissue receiving port area during imaging.

To accommodate each of the different imaging modalities, reusablehandpiece base units specific to each of the imaging environments may beutilized. Each of the handpiece base units may be used for firing and/orrotating the needle aperture, depending upon the operator's needs andthe constrictions of the particular imaging environment. Each of thebase units is designed to accommodate the probe assembly to enable thesame probe to be used across imaging modalities.

FIG. 38 a illustrates a base 420 for use with probe assembly 32 in amammography guided procedure. Base 420 may be attached to thestereotactic arm of a mammography machine by a mounting feature 422. Arecessed nest area 424 is provided in base 420 for accommodating theprobe lower shell. Probe assembly 32 may be lodged in nest 424 prior tothe initiation of a procedure. A firing button 426 is included in base420 for firing the needle of the probe assembly into the tissue mass ofinterest. A knob 430 on the side of base unit 420 compresses a firingspring within the unit. When button 426 is compressed, the spring pushesagainst probe assembly 32 to forcibly drive the entire probe assemblyand nest 424 forward relative to the mounting feature 422.

An aperture rotation gear 432 is also provided in the recessed area ofbase 420 for rotating the tissue receiving port of the probe assemblyafter the needle is positioned within the tissue mass. Aperture rotationgear 432 includes a plurality of gear teeth 434. Gear teeth 434 projectpartially above the recessed surface area to engage similar shaped teethon a second gear integral to the needle support component within probeassembly 32. Teeth on the second, needle gear are recessed within theprobe shell, but accessible by aperture rotation gear 432 when the probeis lodged in nest 424. A knob 436 is provided on the proximal end ofbase 420 for manually rotating gear 432. When gear 432 rotates, theengagement between the gears causes the needle to rotate, therebyrepositioning the tissue receiving port within the tissue mass. Probeassembly 32 can include flexible engagement fingers that lock the needlegear and prevent the gear from rotating outside of nest 424. When probeassembly 32 is inserted into nest 424, the flexible fingers aredeflected so as to disengage from the needle gear, and allow the gear torotate in response to the rotation of base gear 432. FIG. 38 billustrates the probe assembly 32 lodged in nest 424.

FIG. 39 illustrates a similar type of probe base unit for use in anultrasound imaging environment. As shown in FIG. 39, the base unit 440includes a nest 442 for accommodating the lower shell of probe assembly32. A knob 444 is provided for compressing a firing spring within base440, as well as a button 446 for releasing the spring to “fire” theprobe assembly and nest 424 into a tissue mass. In the ultrasoundenvironment, base 440 may be hand-held and manipulated as required bythe operator. Accordingly, a needle rotation mechanism is not necessaryfor base 440, since the operator may rotate the needle by manuallyrotating the base and/or probe assembly.

As shown in FIG. 40, a third type of probe base 450 is provided for usein MRI guided procedures. Base 450 may be mounted to a localization unitwithin the MRI unit. The reduced size of the probe assembly in thepresent invention reduces the structural requirements for thelocalization unit due to the reduced cantilever loading generated by theprobe. MRI base 450 includes a recessed nest 452 for accommodating thelower probe shell. In addition, the base includes an aperture rotationgear 454 having a plurality of gear teeth that engage similar shapedteeth that extend from the probe lower shell. The gear in the lowerprobe shell is attached to the needle to rotate the needle whenever gear454 is rotated, in a manner similar to the mammography nest embodimentshown in FIG. 38. An aperture rotation knob 456 is located on theproximal end of base 450 to manually rotate gear 454 and,correspondingly, the tissue receiving aperture in the needle. Base 450does not require a firing mechanism for positioning the needle withinthe tissue. However, multiple needle lengths may be used with the probeassembly to enable the probe assembly to more easily fit within the MRIunit. The particular needle length selected will depend upon the depthof the tissue mass of interest within the patient's body.

As an alternative to the use of MRI base 450, an MRI localization depthgage 460, such as shown in FIG. 41, may be used for positioning theprobe assembly. In this embodiment, a depth stop 462 is attached to theprobe assembly and/or the needle 80. The depth stop includes anadjustment knob 464 for adjusting the desired depth of the probe needle.After the needle is properly positioned, the probe is inserted into thepatient's tissue until the stop is reached. The patient may then beplaced in the MRI device and imaged without additional support for theprobe assembly. After the needle position within the tissue isconfirmed, the holster is attached to the probe assembly to begin tissuesampling.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the spirit and scope of the appendedclaims. Additionally, each element described in relation to theinvention can be alternatively described as a means for performing thatelement's function.

1. A method of performing a biopsy comprising the steps of: providing a biopsy device comprising a cannula having a tissue receiving port and a cutter assembly comprising a hollow cutter disposed at least partially within the cannula for translation with respect to the cannula, the cutter for severing tissue drawn into the tissue receiving port; positioning the tissue receiving port in the tissue to be sampled; removing the cutter from the biopsy device; imaging the biopsy site associated with the tissue receiving port of the biopsy device after removing the cutter from the biopsy device; inserting the cutter into the biopsy device; and severing tissue received in the tissue receiving port with the cutter.
 2. The method of claim 1 wherein the step of removing the cutter is performed prior to positioning the tissue receiving port in the tissue.
 3. The method of claim 1 wherein the step of removing the cutter is performed after the step of positioning the tissue receiving port in the tissue.
 4. The method of claim 1 further comprising the step of removing the cutter after severing the tissue.
 5. The method of claim 4 further comprising the step of imaging the biopsy site after the step of removing the cutter as recited in claim
 4. 6. The method of claim 1 wherein the step of imaging comprises Magnetic resonance imaging.
 7. A biopsy device comprising: a probe assembly comprising a cutter assembly and a cannula; wherein the cutter assembly comprises a hollow cutter disposed for translation with respect to the cannula; and wherein the hollow cutter is removable from the probe assembly without disassembling the probe assembly and without removing the cannula from the probe assembly.
 8. The biopsy device of claim 7 wherein the hollow cutter is releasably held in the probe assembly, and wherein the hollow cutter is removable along a longitudinal axis of the hollow cutter.
 9. The biopsy device of claim 8 wherein the hollow cutter is releasably held in the probe assembly by a latch.
 10. The biopsy device of claim 7 wherein the hollow cutter is adapted to be removed from or inserted into the probe assembly when the cannula is positioned in tissue.
 11. The biopsy device of claim 7 wherein the probe assembly comprises a proximal opening for receiving the hollow cutter.
 12. The biopsy device of claim 7 wherein the probe assembly is releasably mountable to a holster. 